Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 10 Answered

A.P
Asked by rohitkumarh94 | 15 Mar, 2010, 07:47: PM
Expert Answer

Sn = n(2a0+(n-1)d)/2

S10 = 10(2a0+9d)/2 = -80.

2a0+9d = -16  ... (1)

Sum of next 10 terms is, S20 - S10 , which is

20(2a0+19d)/2 - 10(2a0+9d)/2 = -280

2a0 + 29d = -56  ..... (2).

Solving (1) and (2),

d = - 2 and a0 = 1

Hence the AP is, 1, -1 , -3, -5, -7, ....

Regards,

Team,

TopperLearning.

 

Answered by | 16 Mar, 2010, 07:52: AM
CBSE 10 - Maths
Asked by hanugraha | 30 May, 2010, 07:53: PM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by hanugraha | 30 May, 2010, 07:13: PM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by 2806rahul | 30 May, 2010, 09:28: AM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by shobhitdc | 29 May, 2010, 04:59: PM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by ROJAAPPA | 29 May, 2010, 12:58: PM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by shobhitdc | 29 May, 2010, 11:59: AM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by shobhitdc | 29 May, 2010, 10:52: AM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by devanshmudgal | 28 May, 2010, 07:31: PM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by shobhitdc | 28 May, 2010, 01:12: PM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by shobhitdc | 28 May, 2010, 01:08: PM
ANSWERED BY EXPERT
Season Break Offer!
Get 60% Flat off instantly.
Avail Now
×